PRACH Signal Demodulation with Sounding Reference Interference Removal
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Solution Overview
Problem
In LTE networks, the interference from sounding reference signals can severely damage the cross-correlation of Zadoff-Chu sequences used in PRACH, leading to false alarms during PRACH detection due to overlapping time-frequency domains between PRACH and sounding reference signals from neighboring or local cells.
Innovation Solution
A method and apparatus that acquire a down-sampling sequence of the PRACH signal, determine the position of the sounding reference signal sampling point through power sequence analysis, and eliminate the interference by setting the corresponding sampling points to zero, allowing for coherent detection of the PRACH signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent demodulation is performed on PRACH sequence, then PRACH detection accuracy is improved, but false alarm rate increases due to interference from sounding reference signal sequence
Solution Approach 1:
The patent extracts and removes the sounding reference signal sequence from the received signal before performing coherent demodulation on the PRACH sequence. By separating the harmful interference component (sounding reference signal) from the useful signal (PRACH), the method eliminates the source of false alarms while preserving the integrity of PRACH detection
Solution Approach 2:
The patent applies preliminary anti-action by pre-processing the received signal to eliminate the sounding reference signal interference before the coherent demodulation process. This preliminary removal of harmful interference prevents the interference from affecting the subsequent PRACH detection, thereby avoiding false alarms
2Adaptability or versatility
If time-frequency domain resources are allocated for both PRACH and sounding reference signal, then system functionality is improved, but interference between the two signals occurs
Solution Approach 1:
The patent converts the harmful interference from sounding reference signals into a beneficial process by using the known structure and properties of the sounding reference signal (Zadoff-Chu sequence characteristics) to identify, extract, and remove it from the composite signal. The interference, rather than being avoided, is actively utilized as a detection target for removal
Solution Approach 2:
The patent introduces an intermediary processing step between signal reception and PRACH demodulation. This intermediary process involves correlating the received signal with the known sounding reference signal sequence to identify and isolate the interference component, which is then removed before the actual PRACH detection takes place
Data Source
AI summary
Embodiments of the present invention provide a method and an apparatus for demodulating a physical random access channel signal. The method includes: acquiring a down-sampling sequence of a PRACH demodulation signal, and acquiring a power sequence of the down-sampling sequence; determining a position of a sounding reference signal sampling point in the down-sampling sequence according to the power sequence; and eliminating the sounding reference signal sampling point in the down-sampling sequence according to the position of the sounding reference signal sampling point, so as to perform PRACH coherent detection on a down-sampling sequence obtained after the sounding reference signal sampling point is eliminated. In the method and the apparatus for demodulating a physical random access channel signal in the embodiments of the present invention, interference from a sounding reference signal can be restrained and false alarms in PRACH detection can be reduced.